Stainless Steel Hardware The Clamp Post mount with 25mm (1 inch) Ball is designed for wide range clamping. The heavy-duty mount is made of high-strength composite materials with corrosion-resistant stainless-steel hardware. The clamp mount opens to 2.75 diameter to securely grip roll bars, tubes, handlebars, warehouse carts, etc. The 25mm ball (1 inch) is compatible with 25mm (1 inch) shafts. COMPATIBLE SHAFTS:HEIGHT- MODEL #SP-RM250 3.75 inches MODEL #SP-RMS250 2.75 inches MODEL #SPRMET 3.75 inches MODEL #SPRMSMET-B 2.75 inches MODEL #SPRM256B 6 inches